I often hear faculty complain that students don't even do a simple spell check before turning in a project or paper. Dr. Douglas Eder from Southern Illinois University shared with me a solution that he posts in his syllabus. He says that it only takes a student one returned paper to convince them to be more careful with the next. It is called the Fatal Error List.
A Fatal Error List
1. Each different word misspelled
2. Each sentence fragment
3. Each run-on sentence or comma splice
4. Each mistake in capitalization
5. Each serious mistake in punctuation that obscures the meaning
6. Each error in verb tense or subject/verb agreement
7. Lack of conformity with assigned format
8. Each improper citation, or lack of citation, where one is needed
Papers with more than 3 Fatal Errors marked by a professor on any 1 page, will be returned to the student. Students are allowed 1 resubmit within 24 hours, and grade will be lowered by 1 grade.
Your list might be different and could include other things. You might have different consequences. But, start from the beginning with clear and specific expectations, so students know how to succeed in your class.